Yoshihiro Tanno

Eos: a novel member of the Ikaros gene family expressed predominantly in the developing nervous system

We identified a novel member of the Ikaros gene family, which has critical roles in the development of lymphoid lineages. This gene, which we named Eos, was expressed predominantly in the developing central and peripheral nervous system. Eos protein could interact with itself and Ikaros protein through its C‐terminal portion in the yeast two hybrid assay. These findings suggested that Eos may have important roles in neural development similarly to the Ikaros family in the development of hemolymphoid tissue.

Rebleeding from ruptured intracranial aneurysms in North Eastern Province of Japan. A cooperative study

OBJECT Rebleeding from ruptured intracranial aneurysms is a major cause of death and disability. With regard to the factors that precipitate the rebleeding and influence the time course after initial bleeding, previous reports differ in their results, and the number of patients investigated was not sufficient for valid conclusions. This study was thus designed to clarify the factors related to rebleeding from ruptured intracranial aneurysms in a large group of patients of the North Eastern Province of Japan. METHODS We found 181 patients with rebleeding after hospitalization among 5612 cases of ruptured intracranial aneurysms from January 1997 to December 2001 in 33 major hospitals in the North Eastern Province of Japan. We analyzed the data with respect to the time course after bleeding and rebleeding, the arterial blood pressure, the situation when rebleeding occurred, the methods of neuroimaging, the level of consciousness, the treatment and the outcome. RESULTS Of 181 patients who were hospitalized, rebleeding occurred in 65 (35.9%) within 3 h and 88 (48.6%) within 6 h after the initial subarachnoid hemorrhage (SAH). The consciousness level before the rebleeding varied widely in distribution, but belonged to the drowsiness or less [Japan coma scale (JCS) single-digit] in 83 patients (45.8%), but after rebleeding, JCS triple-digits (semicoma to coma) included 152 patients (84.0%). Systolic arterial blood pressure prior to rebleeding was most commonly between 120 and 140 mmHg. Rebleeding did occur more frequently during angiography (totally 29 patients, 20%) and much less frequently during 3D-CTA and MRA procedures (a single case). Treatment consisted of aneurysm neck clipping in 72 patients (40.0%), endovascular therapy with coils in 4 patients (2.2%) and conservative ones in 103 patients (56.9%). As to outcome, 109 patients with rebleeding (60.2%) died in 3 months following initial SAH. CONCLUSION Rebleeding occurs more frequently in the earlier period after the initial SAH than previously believed. Thus, more aggressive pharmacologically induced systemic arterial hypotension appears to be important for preventing rebleeding but ultimate outcome of more aggressive hypotension is yet to be determined. If feasible, in order to avoid catheter-angiography related rebleeding, evaluations solely with 3D-CTA and MRA should be in consideration and earlier surgical intervention seems essential as rebleeding does occur often within the first 3 h of onset.

Expression of sonic hedgehog signal transducers, patched and smoothened, in human basal cell carcinoma

In basal cell nevus syndrome (BCNS) patients, mutations of a gene, patched (ptc), which encodes a putative signal transducer of sonic hedgehog protein (SHH), were found and are thought to be one of the major causes of BCNS. The SHH signaling pathway is an important developmental pathway, and ptc protein (PTC) is a suppressive component serving as a receptor for the secreted SHH. Another transmembrane protein, smoothened (SMO), forms a complex with PTC and regulates this signaling pathway. Recent transgenic studies have strengthened the importance of the SHH signaling system in the etiology of basal cell carcinoma (BCC). In this study, we examined the expression patterns of mRNA for ptc and smo in two different BCC subtypes and normal skin. We found that the expressions of ptc and smo mRNA were enhanced in the tumor nests of the nodular BCC, especially at the advancing portions, but were under the detectable level in the superficial BCC cases examined, indicating that ptc and smo mRNA expressions might be associated with BCC tumor progression and divide the BCC histologic types into two subtypes, superficial and nodular types. In addition, no obvious signals for ptc and smo mRNA were detected in the normal human epidermis, appendages, or seborrheic keratosis, indicating that the abnormal proliferation of follicular epithelial cells caused by ptc, smo and/or other genetic changes, which also cause ptc and smo overexpressions, might result in BCC tumor formation.

Expression pattern of a novel death-promoting gene, DP5, in the developing murine nervous system

We examined the expression patterns of the DP5 gene, which encodes a protein with apoptosis-inducing activity, in the developing nervous system of mice. This gene was primarily expressed in the spinal motor neurons and peripheral sensory ganglia of mouse embryos and transiently in the postnatal brain, particularly in the entorhinal cortex and hippocampus. These expression patterns suggest that the DP5 gene may be involved in the apoptosis, if not all, of the developing nervous system.

LIM-Homeodomain Gene Family in Neural Development

In the present study, we isolated five murine LIM-homeodomain (LH) genes including a novel gene designated as L3 which is expressed specifically in the medial ganglionic eminence of the embryonic brain and the mesenchyme surrounding the oral cavity. The comparison of the expression domains in the embryonic forebrain using in situ hybridization histochemistry proved that three LH genes (LH-2, lim-1, and L3) share sharp boundaries. In addition to the prosomeric boundaries in the diencephalon, this gene family defines novel boundaries in the basal telencephalon, the mesencephalon, and the rhombencephalon. These mutually exclusive expression domains suggest that this family might be involved in controlling the early compartmentalization and boundary formation of the developing central nervous system.

Localization of huntingtin-interacting protein-2 (Hip-2) mRNA in the developing mouse brain.

Huntingtin-interacting protein-2 (Hip-2) was identified as a human protein specifically associated with huntingtin in vitro, a gene product affected in patients with Huntington disease (HD). It is a ubiquitin-conjugating enzyme identical to the previously characterized bovine E2-25k. We identified the mouse Hip-2 homologue (mHip-2) and examined its distribution patterns in the developing mouse brain in order to gain an insight into the functional significance of the Hip-2 protein in the normal brain as well as in the pathogenesis of HD. As reported with huntingtin, the mHip-2 mRNA expression developed in parallel with neuronal maturation and became distributed widely in the postnatal mouse brain. This spatiotemporal pattern of mHip-2 mRNA expression resembled that of huntingtin. We further demonstrated that mHip-2 mRNA was colocalized with huntingtin-like immunoreactivity in a single neuron. These findings suggested that the Hip-2 interacted with huntingtin in vivo and played an important role in HD pathogenesis.

Developmental expression of hip-1 and hip-2 mRNA in the mouse central nervous system

’ The Center of Japan Biol. Chem., Kaizu, Gifu 503-0651, * Dept. of Physiol., Nagoya City Univ. Med. Sch., Nagoya 467-8601 and 3 Department of Physiology, Inst. Med.Sci., Banaras Hindu Univ., Varanasi, India Systemic administration of 3-NPA produces striatal specific astrocyte loss associated with destruction of blood-brain barrier. The in viva application of 3-NPA to the mixed cultures demonstrated greater vulnerability of astrocytes than neurons. Since endothelial cells are the first ones to be exposed to the toxin when it enters the circulation, we examined the effect of 3NPA on these cells. The human brain microvascular endothelial cells were exposed to 3-NPA or sodium nitroprusside (SNP) or their combination for 24 h and the nitrite concentration of medium (indicator of NO activity) and cell numbers were determined. The 3-NPA (1.7 mM) increased nitrite levels in presence or absence of cells in the medium and was associated with 50 % decrease in number of cells. SNP (0.004-0.4 uM) also increased the nitrite concentration in dose-dependent manner in presence of cells, but without cells the increase was only seen with 0.4 PM. The increase of nitrite by SNP was positively correlated with the cell loss. The nitrite concentration remained almost same with SNP (0.004-0.4 t&l) in presence of 3-NPA but there was greater cell loss for the same concentration of nitrite. The results indicate that the 3-NPAinduced toxicity of endothelial cells mediated by NO and non-NO mechanisms.

1031 Expression of the members of ubiquitin conjugating enzyme gene family in the developing nervous system

Kazutada Watanabe, Junko Ogawa, Harumi Kaneko, Saburo Nagata, Hiroko Hosoya We cloned two novel cDNAs encoding adhesion molecules, NB-2 and NB-3, in the Contactin/F3 subgroup. NB-2 and NB-3 are comprised of 1099 and 1028 amino acid residues, respectively. NB-2 shared 51% similarity with NB-3 in amino acid sequence. The amino acid sequence of NB-2 exhibited 46, 43, 55 and 55% identities with Contactin/FS, Tag-l, Big-l and Big-2, respectively. Likewise, the amino acid sequence of NB-3 showed 42, 44, 58 and 60% identities with Contactin/F3, Tag-l, Big-l and Big-2, respectively. Northern blot analysis revealed that NB-2 mRNA was detected in cerebrum and cerebellum, but not in spinal cord. On the other hand, the expression of NB-3 mRNA was high not only in cerebrum and cerebellum, but also in spinal cord. The expression of both mRNAs was developmentally regulated. The maximum expression of both molecules in cerebrum was observed at postnatal 6th day. The results of in situ hybridization in rat brain will be presented.

1331 Identification of mouse homologues of eyes absent (eya), a drosophila gene involved in neuronal cell death

Cerebellar granule cells isolated from 7-day-old postnatal rats undergo massive degeneration around DIV 5-6, which appears to mimic neuronal death due to unavailable trophic factor that occurs during development. In support of this notion, this neuronal death was prevented by treating the cells with cycloheximide (0.1-l PM) or cordycepin (l-3 PM), suggesting that it is an active process requiring protein and RNA synthesis. It was previously shown that both chronic depolarization with high potassium and NMDA prevent this neuronal death in a dose-dependent manner. In addition to this, brain-derived neurotrophic factor (BDNF; 50 rig/ml) completely prevented this neuronal death. Moreover, we found that the commitment point of cycloheximide preceded that of BDNF by 0.5 day, suggesting that BDNF is capable of promoting granule cell survival through a post-translational mechanism. We also have been characterizing this programmed cell death (PCD) in terms of the expression of certain genes during this PCD of cerebellar granule cells in vitro.